Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/54—Silicon-containing compounds
  • C08K5/5403—Silicon-containing compounds containing no other elements than carbon or hydrogen
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F110/00—Homopolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
  • C08F110/04—Monomers containing three or four carbon atoms
  • C08F110/08—Butenes
  • C08F110/10—Isobutene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F8/00—Chemical modification by after-treatment
  • C08F8/02—Alkylation
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F8/00—Chemical modification by after-treatment
  • C08F8/26—Removing halogen atoms or halogen-containing groups from the molecule
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2810/00—Chemical modification of a polymer
  • C08F2810/30—Chemical modification of a polymer leading to the formation or introduction of aliphatic or alicyclic unsaturated groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2810/00—Chemical modification of a polymer
  • C08F2810/40—Chemical modification of a polymer taking place solely at one end or both ends of the polymer backbone, i.e. not in the side or lateral chains

Definitions

• organo­silicon compounds During the last two decades a variety of organo­silicon compounds have been shown to react with various electrophilic reagents. Reactions may occur with organo­silicon compounds containing multiple bonds which are one, two or three atoms removed from silicon, i.e., with aryl­silanes, vinylsilanes, alkynylsilanes, silyl enol ethers, allylsilanes, benzylsilanes, homoallylsilanes and under vigorous conditions also with alkylsilanes. Most of these reactions are envisioned to proceed by electrophilic attack leading to an intermediate cation beta to silicon. Such reactions are highly regioselective due to cation stabilization. The silyl group is usually lost during subsequent steps leading to compounds having the electrophile and the multiple bond in predictable locations.
• organosilicon compounds are one of the least explored synthetic techniques in polymer synthesis. Due to the relatively weakly polarized silicon-carbon bond organosilanes behave as weakly reactive organometallic compounds. Thus, they can be handled more conveniently than other organometals, i.e., they do not usually require anhydrous or inert atmospheres and are inert in the presence of a great variety of functional groups. Little work has been done on electrophilic substitution of organosilicon compounds with carbocations or species bearing a relatively high positive charge on the carbon atom. Adamantyl and tert-butyl halides have been demonstrated to undergo substitution in the presence of Lewis acids with select unsaturated organosilicon compounds. (See for example, I. Fleming et al. Synthesis, 1979, 446; T. Sasaki et al., J. Org. Chem., 1980(45), 3559.)
• Polyisobutylene has limited utility because it is hard to crosslink. Copolymerization with small amounts of isoprene was found to give residual sites of unsaturation which thus permitted sulfur vulcanization, resulting in the commercialization of butyl rubber during World War II. Besides chemical and ozone inertness, butyl rubber has very low permeability to gases and has thus found widespread use in tire inner tubes. Low molecular weight polyisobutylene oils are currently used to increase the viscosity of lubricating oils and the higher molecular weight unvulcanized polymer is used in adhesives, caulks, sealants, and polymer additives.
• isobutylene is polymerized with aluminum chloride at reaction temperatures as low as -100 degrees Centigrade.
• the product has mostly saturated aliphatic end groups.
• Polyisobutylene (PIB) containing sites of unsaturation can be produced by copolymerization of isobutylene with small amounts of isoprene. The resulting unsaturation permits vulcanization, but because the sites are mainly internal, hydrosilylation is inhibited or prevented.
• an (AB) block copolymer may form, where A represents the siloxane block and B represents the hydrocarbon block.
• Another approach has been to make a polymer with chlorine at each end by using a special dichlorocarbon coinitiator such as para dicumyl chloride with BCl3, or by using chlorine as a coinitiator.
• the present invention relates to a method of preparing allyl-terminated polyisobutylene (PIB) by allylation with allyltrimethylsilane of tertiary chloro­capped PIB by electrophilic substitution.
• the synthesis is the first example of the use of the silyl synthon allyltrimethylsilane in polymer chemistry.
• the synthesis begins with the BCl3 catalyzed mono- or oligo-tertiary­chloride "inifer" initiated polymerization of isobutylene, followed in the same reaction vessel by the addition of hexane, allyltrimethylsilane, and TiCl4.
• This method is produced allyl terminated PIB.
• the present invention is directed toward a process for the synthesis of novel telechelic, or terminally functional polymers such as polyisobutylenes carrying terminal unsaturations such as allylic groups.
• a chlorine functional or chlorine/olefin mixed functional telechelic isobutylene which, in turn, involves polymerization of the monomer and a multifunctional compound capable of simultaneously initiating polymerization and acting as a transfer agent.
• the term inifer has been employed, derived from the words initiator and transfer.
• an object of the present invention to provide novel telechelic allyl-terminated polyisobutylene polymers. It is another object of the present invention to provide a process for the synthesis of polyisobutylenes carrying terminal sites of allylic unsaturation.
• the invention relates to a method of preparing in a one reaction vessel two step process allyl-terminated PIB by the allylation with allyltrimethylsilane of tertiary chloro end-capped PIB by electrophilic substitution.
• tertiary chloro end-capped PIB or “tertiary chlorinated polyisobutylene” in the present invention is meant polyiso­butylene molecules having at least one tertiary carbon atom to which is bonded a chlorine atom.
• the invention further relates to a procedure in which a prepolymer of PIB is prepared from isobutylene (IB) by the inifer method in the presence of BCl3 and inifer.
• the reaction mixture resulting from polymerizing the IB to PIB is not quenched but instead an excess of a mixture of allyltrimethylsilane and a Friedel-Crafts type Lewis acid catalyst, preferably TiCl4, is added.
• the instant invention relates to a method of preparing allyl-terminated polyisobutylene polymer which method comprises reacting tertiary chlorinated polyiso­butylene with allyltrimethylsilane in the presence of boron trichloride and titanium tetrachloride, tin tetrachloride, or, in the absence of boron trichloride, dialkyl aluminum chloride, such as but not limited to diethyl aluminum chloride, whereby allyl-terminated polyisobutylene polymer is produced.
• Alkyl aluminum chlorides with alkyl groups of one to six carbon atoms are also operative in the instant invention.
• the instant invention further relates to a method of preparing allyl-terminated polyisobutylene polymer which method comprises
• a preferred embodiment, therefore, of the present invention is the "one reaction vessel two step” allylation of PIB in which the reaction medium mixture of approximately 80% methyl chloride/20% hexane used to polymerize the IB to PIB, is changed by adding hexane to be approximately 45:55 CH3Cl:hexane.
• Another preferred embodiment of the present invention is the "two reaction vessel two step” allylation of PIB wherein the 80% methyl chloride/20% hexane mixture used for the polymerization of IB to PIB is replaced in the second step with a solvent composition of 45:55 CH2Cl2:hexane.
• the hexane concentration can thus be increased to a concentration in the range of 55 to 70 weight per cent.
• Diethylaluminum chloride ((CH3CH2)2AlCl) was obtained from Ethyl Corporation, Baton Rouge, LA.
• Boron trichloride (BCl3) was obtained from Union Carbide Company, Danbury, CT.
• Titanium chloride (TiCl4) was obtained from Aldrich Company, Milwaukee, WI.
• Tin chloride (SnCl4) was obtained from Fisher Company, Pittsburgh, PA. Allyltri­methylsilane was obtained from Petrarch Systems Inc., Bristol, PA.
• Chloro PIB was prepared by the semicontinuous inifer method of Kennedy et al. (J. Polym. Sci., Polm. Chem. Ed., 18 , 1523 1980).
• Isobutylene (0.0224 moles) was polymerized at -80 degrees Centigrade for 60 minutes by passing it into 25 milliliters of a 80 parts methyl chloride and 20 parts hexane solution of 0.000281 moles of para-dicumyl chloride, 0.00154 moles BCl3, in a culture tube. After one hour, the solvent composition was changed by adding hexane to be 45:55 CH3Cl:hexane.
• Chloro PIB was prepared by the semicontinuous inifer method of Kennedy et al. (J. Polym. Sci., Polm. Chem. Ed., 18 , 1523 1980). Approximately 0.5 grams tertiary chloro-ended PIB was dissolved in 5 milliliters of dichloro­methane and placed in a 50 milliliter glass reactor equipped with a Teflon stopcock. A three to five fold molar excess of allyltrimethylsilane relative to the tertiary chloro-end groups was added with a syringe under nitrogen. The reaction was initiated by adding a two to three fold molar excess of TiCl4 Lewis acid with a syringe under nitrogen.
• the homogeneous charge was occasionally agitated and after 25-75 minutes was poured into saturated NaHCO3 solution (25 milliliters).
• the organic phase was separated, dried over anhydrous MgSO4, and the volatiles were evaporated in vacuo.
• the polymer residue was dissolved in a small amount of hexane (approximately 2 milliliters), precipitated with acetone, separated, washed with acetone, and the volatiles were removed by evaporation in vacuo overnight.
• the dry polymer was dissolved in CCl4 (20-30%) and subjected to proton NMR analysis which confirmed the formation of allyl PIB.
• Polymerization of isobutylene was carried out in a culture tube by rapidly adding 0.80 milliliters of BCl3 to 22 milliliters of a stirred solution of 0.063 moles/dm3 cumyl chloride and from 0.065 to 0.180 moles/dm3 of allyltrimethyl­silane and 1.2 moles/dm3 of isobutylene.
• the reaction was terminated by th addition of a few milliliters of prechilled methanol and the precipitated allyl terminated PIB polymer was isolated.
• Isobutylene (0.0224 moles) was polymerized at -80 degrees Centigrade for 60 minutes by passing it into 25 milliliters of a 80 parts methyl chloride and 20 parts hexane solution of 0.000562 moles of para-dicumyl chloride, 0.00308 moles BCl3, in a culture tube. After one hour, the reaction was terminated and the chloro-PIB was isolated and washed to remove any residual BCl3. The chloro-PIB, 1.0 gram, was then taken up in 10 milliliters of a solvent composition of 45:55 CH2Cl2:hexane.
• Example 5 Diethyl Aluminum Chloride Catalyzed Allylation of Chloro PIB.
• Isobutylene (0.0224 moles) was polymerized at -80 degrees Centigrade for 60 minutes by passing it into 25 milliliters of a 80 parts methyl chloride and 20 parts hexane solution of 0.00562 moles of para-dicumyl chloride, 0.00308 moles BCl3, in a culture tube. After one hour, the reaction was terminated and the chloro-PIB was isolated and washed to remove any residual BCl3. The chloro-PIB, 1.0 gram, was then taken up in 10 milliliters of a solvent composition of 45:55 CH3Cl:hexane.

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• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
• Transition And Organic Metals Composition Catalysts For Addition Polymerization (AREA)

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• 1986
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